If you are have issues getting Asp.net 2.0 membership and personalization running under Vista then you are not alone: there seems to be security issues dynamically creating the database.

Luckily the workaround is pretty straight forward, all you have to do is:

1.  Install SQL Server 2005 Developer edition

2. Create a Database

3. Run the ASPNET_REGSQL utlity 

4. Tell ASP.NET 2.0 to use this database with

<connectionStrings>

<remove name="LocalSqlServer"/>

<add name="LocalSqlServer" connectionString="Data Source=localhost;Initial Catalog=aspnet;Persist Security Info=True;User ID=sa;Password=Pwd;Pooling=False"/>

</connectionStrings>

Luckily ScottGu has documented these steps  at:

http://weblogs.asp.net/scottgu/archive/2005/08/25/423703.aspx